Measuring load on a drilling derrick during operations

ABSTRACT

An elongatable beam extends between two points on the derrick. The elongatable beam is configured to produce a strain stream responsive to a change in a length of the elongatable beam. The length of the elongatable beam is configured to change responsive to flexing of the derrick due to a derrick load. A controller is operatively coupled to the elongatable beam. The controller configured to receive the strain stream from the elongatable beam and determine a derrick load responsive to the received strain stream.

TECHNICAL FIELD

This disclosure relates to drilling and wellbore operations.

BACKGROUND

During wellbore operations, downhole tubulars, such as tools, drill pipes, casings, production tubing, etc., sometimes need to be retrieved from the wellbore. To facilitate such retrieval, drill rigs are deployed to the wellbore to “fish” out the desired components. Fishing operations typically include lowering a fishing tool into the wellbore and securing the components to the tool. Once the component is secured to the fishing tool, the component is drawn out of the wellbore by retracting a cable onto which the fishing tool is attached. The cable is often a part of a system referred to as a draw-works, which includes cabling, pulleys, and winches secured to the rig. The cabling itself transfers the tension it experiences into the drill derrick.

SUMMARY

This disclosure describes technologies relating to measuring load on a drilling derrick during operations.

An example implementation of the subject matter described within this disclosure is a derrick with the following features. An elongatable beam extends between two points on the derrick. The elongatable beam is configured to produce a strain stream responsive to a change in a length of the elongatable beam. The length of the elongatable beam is configured to change responsive to flexing of the derrick due to a derrick load. A controller is operatively coupled to the elongatable beam. The controller configured to receive the strain stream from the elongatable beam and determine a derrick load responsive to the received strain stream.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The elongatable beam is anchored to each of the two points.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The controller is further configured to determine that the derrick load has exceeded a predetermined threshold and cease operations of the derrick responsive to determining that the derrick load has exceeded the predetermined threshold.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The predetermined threshold is 85% of a rated load capacity of the derrick.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. A draw-works system is coupled to the controller. The draw-works system includes a cable and a winch. The cable is supported by the derrick. The draw-works system is configured to adjust a load on items supported by the derrick. The controller is further configured to cease operations by shutting down the draw-works system.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The elongatable beam includes a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The derrick extends vertically in-line with a wellbore, wherein the elongatable beam is arranged as a transverse member of the derrick.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The elongatable beam is a load-bearing member.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The elongatable beam is a first elongatable beam. The strain stream is a first strain stream. The derrick load is a first derrick load. The derrick further includes a second elongatable beam extending between two points on the derrick. The second elongatable beam is configured to produce a second strain stream responsive to a length of the second elongatable beam. The controller is further configured to receive the second strain stream and determine a second derrick load responsive to the received second strain stream.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The controller is further configured to compare the first derrick load and the second derrick load. The controller is configured to determine that the first derrick load and the second derrick load differ by a predetermined amount. The controller is further configured to produce a warning responsive to determining the first derrick load and the second derrick load differ by the predetermined amount.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The predetermined amount is substantially 5%.

Aspects of the example derrick, which can be combined with the example derrick alone or in combination with other aspects, include the following. The first elongatable beam and the second elongatable beam include different base technologies.

An example implementation of the subject matter described within this disclosure is a method with the following features. A length of an elongatable beam of a derrick is changed responsive to a load being received by a derrick. The elongatable beam extends between two points on the derrick. A change in length of the elongatable beam is measured. A magnitude of the load is determined responsive to measuring the change in length of the elongatable beam.

Aspects of the example method, which can be combined with the example method alone or in combination with other aspects, include the following. A magnitude of the load is determined to exceed a specified threshold. Operations involving the derrick are ceased responsive to determining that a magnitude of the load exceeds a specified threshold.

Aspects of the example method, which can be combined with the example method alone or in combination with other aspects, include the following. Ceasing operations includes shutting down a draw-works system.

Aspects of the example method, which can be combined with the example method alone or in combination with other aspects, include the following. The specified threshold is 25% of a rated load capacity of the derrick.

An example implementation of the subject matter described within this disclosure is a drilling rig with the following features. An elongatable beam extends between and anchored to two fixed points on a derrick. The elongatable beam is configured to produce a strain stream responsive to a length of the elongatable beam. A draw-works system is configured to adjust a load on items supported by the derrick. A controller is configured to receive a strain stream from the elongatable beam and determine a load responsive to the received strain stream.

Aspects of the example drilling rig, which can be combined with the example drilling rig alone or in combination with other aspects, include the following. The controller is further configured to determine that the load has exceeded a predetermined threshold and cease operations of the draw-works system responsive to determining that the load has exceeded the predetermined threshold.

Aspects of the example drilling rig, which can be combined with the example drilling rig alone or in combination with other aspects, include the following. The pre-determined threshold is 25% of a maximum load of the derrick according to finite element analysis of the derrick.

Aspects of the example drilling rig, which can be combined with the example drilling rig alone or in combination with other aspects, include the following. The elongatable beam includes a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor.

Aspects of the example drilling rig, which can be combined with the example drilling rig alone or in combination with other aspects, include the following. The elongatable beam is arranged as a transverse member of the derrick.

Aspects of the example drilling rig, which can be combined with the example drilling rig alone or in combination with other aspects, include the following. The elongatable beam is a load-bearing member.

Particular implementations of the subject matter described in this disclosure can be implemented so as to realize one or more of the following advantages. Aspects of this disclosure can add an additional layer of safety to rigs and can prevent catastrophic failure of derricks on rigs.

The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example wellsite.

FIG. 2 is a block diagram of a controller that can be used with aspects of this disclosure.

FIG. 3 is a flowchart of an example method that can be used with aspects of this disclosure.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

During fishing operations within a wellbore, tubulars, such as drill pipes, casings, production tubing, etc., can become stuck. In such a situation, vertical loads are applied to the stuck pipe, and subsequently the derrick of the drilling rig. In some instances, the load gauge that is typically used on the rig can be broken or miss-calibrated, resulting in false readings. In such instances, this false reading can cause the load to exceed the derrick capacity, leading to structural failure and collapse. To prevent the rig failure, the deflection and flex of the derrick can be monitored.

This disclosure relates to a drilling rig with a derrick that includes an elongatable beam that is able to elongate when the derrick is under load. The elongation is measured during rig operations. Once the member extends beyond a specified threshold, a warning or shutdown signal can be produced.

FIG. 1 is a schematic view of an example wellsite 100. The drill site 100 includes a wellbore 102 formed within a geologic formation 104. At an uphole end of the wellbore 102 is a drill rig 106 that includes a derrick 114. The drill rig also includes a draw-works system 107. The draw-works system 107 includes a winch 108 that draws or releases a cable 110. The cable 110 is connected to the derrick 114 with one or more pulleys 115 such that the derrick supports the load on the cable 110. That is, as tension within the cable 110 increases, a load on the derrick 114 increases. The draw-works system 107 is used to trip (that is, insert and remove) tubulars into and out of the wellbore 102. In the illustrated scenario, the cable is supporting a fishing tool 112 at a downhole end of the cable 110. The fishing tool 112 is supporting a tubular 116 that is being drawn from the wellbore 102.

The derrick 114 includes an elongatable beam 118 extending between two points on the derrick 114. That is, each end of the elongatable beam 118 is coupled to a portion of the derrick 114 such that the ends or the elongatable beam 118 move in unison with the two points. In other words, each end of the elongatable beam 118 is anchored to the two points. For example, the elongatable beam can be anchored by welds, fasteners, or adhesive. The elongatable beam 118 is configured to produce a strain stream responsive to a change in a length of the elongatable beam 118; however, in some implementations, the elongatable beam 118 can produce a strain stream even during static conditions. Such a strain stream can be used for calibration purposes. Various technologies can be used for the elongatable beam 118, examples of which are described throughout this disclosure. When the derrick 114 is under load, that is, when the cable 110 is in tension, the derrick 114 experiences a degree of flex throughout its structure. The length of the elongatable beam 118 is configured to change responsive to flexing of the derrick 114 due to derrick load. A controller 200 is operatively coupled to the elongatable beam 118 and the draw-works system 107.

The elongatable beam 118 can include a variety of measurement technologies, for example, the elongatable beam 118 can include a strain gauge, a magnetic sensor, an optical sensor, or a fiber optic sensor. In implementations that include a strain gauge, the controller 200 can be electrically coupled to the strain gauge. As the strain gauge changes in length (during high tensile stretch or relaxation), an electrical resistance across the strain gauge changes. This change can be measured by the controller, and a change in length, change in load, or both, can be determined based on the changed resistance. In this instance, the strain stream can include an electrical current that changes based on the changing length of the elongatable beam 118. The electrical current can be interpreted by the controller 200.

In implementations where a magnetic sensor is used, a sensor can be arranged adjacent to a magnet, both being attached to the elongatable beam 118. A change in magnetic field can be detected as the magnet and the sensor change positions relative to one another. In some implementations, a Hall Effect sensor or similar sensor can be used. Similar principles can be used for electric field sensors. The change in magnetic or electric fields can be converted into a voltage, current, or pulse coded modulation signal to produce a strain stream interpretable by the controller 200.

In implementations with an optical sensor, a visual sensor, such as a camera, can be fixed to the elongatable beam 118 or the derrick 114. The optical sensor looks at a graduated scale that can be seen by the optical sensor. As the length of the elongatable member changes, the graduated scale moves relative to the optical sensor. The optical sensor then converts the image (or light intensity, or any other visual data) into a strain stream that is interpretable by the controller 200.

In implementations with a fiber optic sensor, a fiber optic cable is secured to the elongatable beam 118 such that the fiber optic sensor changes length in unison with the elongatable beam 118. In such an implementation, a light-based signal is transmitted through the fiber optic cable to a receiver. As the length of the fiber optic cable changes, different interference patterns are detected by the receiver. These interference signals can be converted into an analog or digital signal interpretable by the controller 200.

In some implementations, direct length measurements can be used, for example, with radar, laser, or acoustic based systems. For these implementations, a signal is transmitted from one point on the elongatable beam 118, and is detected at another point on the elongatable beam 118. In some implementations, the transmission and detection points can be the same, and the detector detects a reflection from a reflection point attached to the elongatable member. Regardless, a time is measured between the transmission and the detection. A change in time correlates proportionally with a change in length. That is, if the time between transmission and detection increases, the length increases. The detector can produce a digital or analog strain stream that is interpretable by the controller 200.

Several arrangements that can be used to measure a length or change in length of the elongatable beam 118 have been described; however, other arrangements can be used without departing from this disclosure. Similarly, several examples of strain streams have been described in association with various arrangements; however, various streams can be produced and used with all of the arrangements described herein. For example, the strain stream can include a digital or analog signal. Similarly, the strain stream can include optical, pneumatic, electrical, acoustic, or hydraulic signals without departing from this disclosure.

As illustrated in FIG. 1, the derrick 114 extends vertically in-line with the wellbore 102. In some implementations, the elongatable beam 118 is arranged as a transverse member of the derrick 114. In some implementations, the elongatable beam 118 is a load-bearing member. For example, in implementations where a strain gauge or a fiber optic sensor are used. In such implementations, the elongatable beam 118 can include a solid beam of sufficient size and strength to act as a primary or secondary member within the derrick 114. In some implementations, the elongatable beam 118 may not be load bearing. For example, the elongatable beam 118 may include a telescoping body that is able to extend and compress freely with negligible force being transferred across the elongatable beam 118. Such an implementation can be used, for example, with an optical or magnetic sensor. In some implementations, a non-load bearing elongatable beam 118 can be fastened to a load bearing member of the derrick. While various arrangements have been described in combination with load-bearing and non-load bearing implementations, other combinations are possible without departing from this disclosure.

In operation, the controller 200 is configured to receive the strain stream from the elongatable beam 118 and determine a derrick load responsive to the received strain stream. In general, determining the derrick load is a function of the original length of the elongatable beam 118, the extended length of the elongatable beam 118, material properties of the elongatable beam, and the cross sectional area of the elongatable beam 118. That is, a load is put on the cable 110 by the winch 108. The load in the cable 110 is transferred directly to the derrick 114. The derrick 114 undergoes deformation/flex while it takes on the transferred load. The deformation/flex changes a length of the elongatable beam 118, which then sends a strain stream to the controller 200. The strain stream is then interpreted by the controller 200, and the controller 200 determines a load on the derrick 114 in response to the received strain stream.

Once the derrick load has been determined, the controller 200 can compare the determined load with a predetermined threshold. For example, when the controller 200 determines that the derrick load has exceeded a predetermined threshold, the controller can then cease operations of the derrick 114 responsive to determining that the derrick load has exceeded the predetermined threshold. For example, the draw-works system 107 can be shut down, responsive to a signal sent by the controller, to relax the load on the cable 110, and therefore the derrick 114. Such a predetermined standard can be determined based upon local standards, regulations, and best practices. Example thresholds are described throughout this disclosure.

In some implementations, the derrick includes a second elongatable beam 120 extending between two points on the derrick 114 that are different from the two points on the derrick 114 coupled to the first elongatable beam 118. The second elongatable beam 120 is substantially similar to the first elongatable beam 118 with the exception of any differences described herein. The second elongatable beam 120 is configured to produce a second strain stream, separate and distinct from the strain stream produced by the first elongatable beam 118. In some implementations, the second elongatable beam 120 uses a different base technology than the first elongatable beam 118. For example, the first elongatable beam 118 may include a fiber optic sensor, while the second elongatable beam 120 may include a magnetic sensor. In some implementations, the first elongatable beam 118 is load bearing and the second elongatable beam is not load bearing, or vice versa. In some implementations, the first elongatable beam 118 and the second elongatable beam 120 are directionally different from one another. For example, the first elongatable beam 118 may be transvers/horizontal, while the second elongatable beam 120 may be diagonal or substantially vertical.

In implementations with a first elongatable beam 118 and a second elongatable beam 120, the controller 200 can further be configured to receive the second strain stream to determine a second derrick load responsive to the received second strain stream. In theory, the first derrick load and the second derrick load should read the same. As such, comparing the two loads can be useful in determining if one of the elongatable members is failing or is out of calibration. For this reason, and many others, the controller 200 can be further configured to compare the first derrick load and the second derrick load. If the controller 200 determines that the first derrick load and the second derrick load differ by a predetermined amount, then the controller 200 can produce a warning responsive to determining if the first derrick load and the second derrick load differ by the predetermined amount. The predetermined amount can be configured by the end user and may be set to local regulations, standards, or best practices. For example, in some implementations, the predetermined amount is substantially 5% (within standard rounding and computational errors).

FIG. 2 is a block diagram of a controller 200 that can be used with aspects of this disclosure. The controller 200 can, among other things, monitor parameters of a wellsite 100 and send signals to actuate and/or adjust various operating parameters of the wellsite 100. As shown in FIG. 2, the controller 200, in certain instances, includes a processor 250 (e.g., implemented as one processor or multiple processors) and a memory 252 (e.g., implemented as one memory or multiple memories including non-transitory computer-readable memories) containing instructions that cause the processors 250 to perform operations described herein. The processors 250 are coupled to an input/output (I/O) interface 254 for sending and receiving communications with components in the system, including, for example, the winch 108. In certain instances, the controller 200 can additionally communicate status with and send actuation and/or control signals to one or more of the various system components (including an actuator system, such as the winch 108) of the wellsite 100, as well as other sensors (for example, the elongatable beam 118 and other types of sensors) provided in the wellsite 100. In certain instances, the controller 200 can communicate status and send actuation and control signals to one or more of the components within the wellsite 100, such as the draw-works system 107. The communication can be hard-wired, wireless, or a combination of wired and wireless. In some implementations, controllers similar to the controller 200 can be located elsewhere, such as in a control room, elsewhere on a site, or even remote from the site. In some implementations, the controller 200 can be a distributed controller with different portions located at the wellsite 100, or off site. Additional controllers can be used throughout the site as stand-alone controllers or networked controllers without departing from this disclosure.

The controller 200 can have varying levels of autonomy for controlling the wellsite 100. For example, the controller 200 can receive the strain stream from the elongatable beam 118, and an operator manually controls a derrick load (using the draw-works system 107) based on the information displayed by the controller 200. Alternatively, the controller 200 can receive the strain stream from the elongatable beam 118, receive an additional input from an operator, and begin controls on a derrick load (using the draw-works system 107) with no other input from an operator.

FIG. 3 is a flowchart of an example method 300 that can be used with aspects of this disclosure. In some implementations, all or portions of the method 300 can be performed by the controller 200. After a load is received by the derrick 114, at 302, a length of an elongatable beam 118 of the derrick 114 is changed responsive to a load being received by the derrick 114. The elongatable beam 118 extends between two points on the derrick, and both ends of the elongatable beam 118 move in unison with the two points. As such, at 304, a change in length of the elongatable beam 118 is measured. At 306, a magnitude of the load is determined responsive to measuring the change in length of the elongatable beam 118.

In some implementations, the determined load can be used for safety systems on a drill rig. For example, in some implementations, a magnitude of the load is determined to exceed a specified threshold. In such implementations, exceeding the specified threshold can result in triggering an alarm, or, in some implementations, operations involving the derrick can be ceased in response to determining that a magnitude of the load exceeds a specified threshold. Examples of such thresholds include ranges that extend between 25% and 85% of a rated load capacity of the derrick. In some implementations, such as when the derrick does not have a certified load rating, the predetermined threshold can be 25% of a maximum load of the derrick according to finite element analysis of the derrick.

In some implementations, two separate load thresholds can be used to determine warning and shut-down responses. For example, a first load threshold can trigger a warning or alarm, and a second load threshold, higher than the first load threshold, can trigger shut-down signals to cease operations of equipment, for example, the draw-works system 107. In some scenarios, the thresholds may be set by local regulations.

While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying drawings do not necessarily require the particular order shown, or sequential order, to achieve desirable results. 

What is claimed is:
 1. A derrick comprising: an elongatable beam extending between two points on the derrick, the elongatable beam configured to produce a strain stream responsive to a change in a length of the elongatable beam, the length of the elongatable beam configured to change responsive to flexing of the derrick due to a derrick load; and a controller operatively coupled to the elongatable beam, the controller configured to: receive the strain stream from the elongatable beam; and determine a derrick load responsive to the received strain stream.
 2. The derrick of claim 1, wherein the elongatable beam is anchored to each of the two points.
 3. The derrick of claim 1, wherein the controller is further configured to: determine that the derrick load has exceeded a predetermined threshold; and cease operations of the derrick responsive to determining that the derrick load has exceeded the predetermined threshold.
 4. The derrick of claim 3, wherein the predetermined threshold is 85% of a rated load capacity of the derrick.
 5. The derrick of claim 4, further comprising a draw-works system coupled to the controller, the draw-works system comprising a cable and a winch, the cable being supported by the derrick, the draw-works system configured to adjust a load on items supported by the derrick, the controller further configured to: cease operations by shutting down the draw-works system.
 6. The derrick of claim 1, wherein the elongatable beam comprises a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor.
 7. The derrick of claim 1, wherein the derrick extends vertically in-line with a wellbore, wherein the elongatable beam is arranged as a transverse member of the derrick.
 8. The derrick of claim 1, wherein the elongatable beam is a load-bearing member.
 9. The derrick of claim 1, wherein the elongatable beam is a first elongatable beam, the strain stream is a first strain stream, and the derrick load is a first derrick load, the derrick further comprising a second elongatable beam extending between two points on the derrick, the second elongatable beam configured to produce a second strain stream responsive to a length of the second elongatable beam, the controller further configured to: receive the second strain stream; and determine a second derrick load responsive to the received second strain stream.
 10. The derrick of claim 9, wherein the controller is further configured to: compare the first derrick load and the second derrick load; determine that the first derrick load and the second derrick load differ by a predetermined amount; and produce a warning responsive to determining the first derrick load and the second derrick load differ by the predetermined amount.
 11. The derrick of claim 10, wherein the predetermined amount is substantially 5%.
 12. The derrick of claim 9, wherein the first elongatable beam and the second elongatable beam comprise different base technologies.
 13. A method comprising: changing a length of an elongatable beam of a derrick responsive to a load being received by a derrick, the elongatable beam extending between two points on the derrick; measuring a change in length of the elongatable beam; and determining a magnitude of the load responsive to measuring the change in length of the elongatable beam.
 14. The method of claim 13, further comprising: determining that a magnitude of the load exceeds a specified threshold; and ceasing operations involving the derrick responsive to determining that a magnitude of the load exceeds a specified threshold.
 15. The method of claim 14, wherein ceasing operations comprises shutting down a draw-works system.
 16. The method of claim 14, wherein the specified threshold is 25% of a rated load capacity of the derrick.
 17. A drilling rig comprising: a derrick; an elongatable beam extending between and anchored to two fixed points on the derrick, the elongatable beam configured to produce a strain stream responsive to a length of the elongatable beam; a draw-works system configured to adjust a load on items supported by the derrick; and a controller configured to: receive a strain stream from the elongatable beam; and determine a load responsive to the received strain stream.
 18. The drilling rig of claim 17, the controller is further configured to: determine that the load has exceeded a predetermined threshold; and cease operations of the draw-works system responsive to determining that the load has exceeded the predetermined threshold.
 19. The drilling rig of claim 18, wherein the predetermined threshold is 25% of a maximum load of the derrick according to finite element analysis of the derrick.
 20. The drilling rig of claim 17, wherein the elongatable beam comprises a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor.
 21. The drilling rig of claim 17, wherein the elongatable beam is arranged as a transverse member of the derrick.
 22. The drilling rig of claim 17, wherein the elongatable beam is a load-bearing member. 